Just some general guidelines for spotting fakes, in any case:
Know what the official artwork looks like. A lot of times, pirates will make their own artwork and sticker-labels; and it's often different than the actual artwork.
Other times you, if it's disc-based, you can spot a burned disc. Some official games (like XBox for example) have special hologram logos on the inner ring, identifying it as an official licensed disc.
On a cartridge, look at the pin-outs on the bottom. Often times, the pirated cartridges have a different number of connections than the original cartridge.
But with today's technology, it can be tough to spot the pirates, sometimes. Those methods aren't always foolproof anymore.
